Southern Ponds & Wildlife Vol 3 #2 (Spring 2004)
Bryan Goldsby, certified aquatic applicator with Aquaservices, Inc.
Coontail, as this plant is most commonly called, can be a beautiful and beneficial aquatic plant in certain situations, and deceptively non-aggressive for long periods. But herein lies the problem, as it rarely remains in small amounts in unmanaged lakes and ponds. Inquiries pour in every summer, and sometimes as late as early winter, pertaining to management methods for this native plant. Most of these inquiries start the same; I’ve noticed it before, but it was never a problem. This is where the deception begins.
Coontail is notorious for lying low and posing as a harmless species, but when it decides it’s ready to spread, beware, because it can cover an entire body of water in one or two growing seasons if the depth is appropriate. Thick mats of vegetation can eliminate access to forage fish and cause oxygen depletion. These mats may also ruin boat motors and swallow up lures, money and time if appropriate actions are not taken. There is no reason to tiptoe around this plant – management methods must be aggressive.
Historical Information And Range
Coontail is native to most calm waters of streams, ponds, lakes, ditches and canals throughout North America, tropical America, and parts of Europe and Asia. It is common throughout the southeastern United States, more times than not causing problems in private lakes and ponds.
Sold by the ornamental pond industry as an aesthetic addition for small backyard ponds, coontail, in small amounts, can have positive effects on the appearance of a pond and the dissolved oxygen in a pond. It can actually add elemental oxygen (O2) to the water, which is something most organisms need to live, however in large amounts it can actually cause O2 depletion at night when the photosynthesis port of the respiratory cycle is shut down. This plant is nice in extremely small ponds where pond management can easily be achieved by removing the plant by hand, but in larger ponds this plant can take over and pose a real threat to fish and other aquatic organisms. It can even out compete truly beneficial aquatic plants that are much less aggressive.
It sounds like a bad Cajun joke, but coontail actually gets its name from a much less offensive creature. The name implies a physical resemblance to a scraggly raccoon’s tail. This plant grows from the bottom of the pond all the way to the top of the water typically when the depth is less than 10 feet. It has been seen growing in much deeper water in lakes and ponds with high visibly where the sunlight can penetrate deeper into the water column and provide the essential energy that derives the plants metabolic activities. Although coontail grows best in water with a temperature of 55 degrees or warmer, it has been observed green and active in the middle of December in water temperatures of 45 degrees F. When observations are made like this, coontail is typically very aggressive during the following growing season.
Coontail leaves look similar to the sharp end of a pitchfork, containing one to two forks. The flower produced is extremely small and therefore not readily recognizable. Coontail reproduces like most plants by pollination and subsequent seed production and germination. It can also reproduce from fragments and from reproductive structures that can be found on its roots. This prolific nature of reproduction makes coontail aggressive an problematic. It’s reproductive behavior is similar to dandelion reproduction and seed formation in early spring. Anyone who has ever mowed a lawn knows how aggressive dandelions can be and how quickly they can repopulate a lawn with flowering stems.
Lake and Pond Management Techniques
There is a bright side to this story. Coontail, although problematic at times, can be controlled fairly easily and economically when the correct techniques are employed. Of course, the first step in any kind of management plan is proper identification of the species to be controlled. After the plant has been identified as coontail, there are many treatment options to be considered including herbicidal treatment, lake or pond drawdown’s during the winter, and harvesting.
Coontail is sensitive to most contact herbicides when they are applied in the appropriate amounts. These herbicides, which include diquat dibromide, endothall, hydrothall, and various chelated copper products. All work by contract and subsequent burning of the vegetation. The only surfaces of the vegetation affected are the exposed parts, thus root structures and other parts of the plant that the herbicide does not come in to contact with will not die and additional treatments will be required. Eventually, with multiple treatments the entire plant will die. Coontail is also susceptible to a systemic herbicide known as fluridone. The term “systemic” means that the herbicide will translocate from the leaves down to the roots and kill the entire plant. Although fluridone works very well, it can only be applied in water bodies with minimal to no water exchange. However, when it can be used, one to two years of control is commonly observed.
Lake drawdown’s are often used to control not only coontail, but also many other submersed species of aquatic vegetation. This method is achieved by draining as much as a third of the given body of water during the winter to expose the lake bottom where the coontail was growing during the previous summer months. The cold winter temperatures kill the exposed vegetation, and hopefully all the underground structures that could potentially lead to new growth. This is a very good method to use, but keep in mind; it can sometimes lead to deeper water infestation.
Cutting and harvesting this plant is the last management technique in the list and it should be the last considered. Coontail has the ability to propagate from fragments and therefore should not be cut unless it is done with a boat that has either harvesting or chipping capabilities. A harvester does just what the name says; it picks the cut plant up on a conveyer belt and loads it onto a barge to be unloaded on the shore. A chipper chops the cut plant up into fragments that are too small to propagate and expels them back into the water.
If you have a lake or pond and come across a small patch of coontail, remember to keep a close eye on it. This plant can quickly become a problem. An active lake or pond management plan that incorporates strategically placed and timed herbicidal treatments should be applied if elimination of the plant is not desired. But, it may be in your pond's best interest, especially where fishing is important, to get rid of the coontail completely and replace it with a less aggressive species of submersed vegetation, an aquatic tree species, or an artificial fish structure.